1. Field of the Invention
The present invention relates to a stereo slide mount. More specifically, the invention relates to a stereo slide mount for providing an accurate solid image by masking outer sides of right and left pictures.
2. Description of the Prior Art
In a stereo slide photographed by a stereo camera of the structure that an interval between optical axes of right and left lenses is fixed, non-overlapping portions that photographing ranges of right and left photographing pictures are not brought into agreement with each other are formed due to a difference in the visual field of the right and left photographing lenses of the stereo camera. These non-overlapping portions do not contribute to forming a solid image when the slides are viewed by using a stereo slide viewer. When the stereo slide that the non-overlapping portions are not masked is viewed by two eyes, the edges of the other windows appear as vertical lines along the boundaries of the overlapping portions and the non-overlapping portions to impair taste. Accordingly, to prevent this, the windows of the stereo slide mount have been formed in a width narrower than the size of the picture of the slide films to mask the non-overlapping portions.
Widths of the non-overlapping portions to be masked increase as the photographing distance of a subject to affect the most influence to matching of right and left pictures approaches. Therefore, there have been provided plural kinds of stereo slide mounts having stepwisely different widths of windows. The stereo slide mount having the width of the window of a suitable masking amount is selected from these stereo slide mounts to mount the slide film. However, it is not easy to judge the masking amount by viewing a pair of slide films cut after each frame, and there arises a problem that the stereo slid mount is frequently erroneously selected.
In obtaining a suitable stereo effect in the stereo slide, it is known that a subject to affect the most influence to matching of right and left images should be disposed at the same positions in the right and left windows of the stereo slide mount. If the positions of the subject are different at the right and left, a natural stereo effect is canceled, but the conventional stereo slid mount does not have a criterion of positioning the right-to-left direction of the film, and it has a disadvantage that is not easy to position the film at the suitable positoin.
The present applicant has proposed a stereo slide system that was so formed that a stereo slide mount and a picture masking amount guide device/stereo slide viewer for a stereo slide photographed by a stereo camera having predetermined positional relationship between the perforations of a film and a photographing picture to eliminate the disadvantages of a conventional stereo slide system (Japanese Patent Application No. 8-029177).
The stereo slide mount of the stereo slide system is constituted by a base frame which is provided with film positioning pins in the circumferences of right and left windows, and a cover frame that gap widths between right and left windows are the same and the widths of the windows are stepwisely different. The picture masking-amount guide device/stereo slide viewer can decide a suitable masking amount by observing a solid image while varying the masking amount of the outer region of the picture of the stereo slide. After the masking amount is determined, the perforations of the film are engaged with the positioning pins of the base frame to position the film, the cover frame of the width of the window corresponding to the determined masking amount is selected, and joined to the base frame. Then, the film is positioned at a predetermined position, and the non-overlapping portions of the outer side of the right and left films are masked to obtain an accurate stereo effect.
The above-mentioned stereo slide mount can be accurately and easily positioned at the time of mounting as described above, but since the plural types of the cover frames of the width of the windows for constituting the mount system has the same gap widths between the right and left windows, the pitch at the center between the right and left pictures is narrowed as the widths of the windows is narrowed and hence the optical angles of the two eyes become different depending upon the pitch of the pictures.
The change of the pitch of the right and left pictures is not so large problem at the time of appreciating at all times, but when various stereo slide having large difference of pitches of the pictures is frequently replaced and appreciated for a long time, the adaption of eyes for the change of the optical angle is delayed to feel discomfort or fatigue.
In order to easily mount and accurately position the stereo slide and to provide a stereo slide mount to be easily seen with small fatigue, it becomes necessary to solve a technical assignment. The object of the present invention is to solve this technical assignment.